LS6 cam or Modern equiv in SS454 Monte

[VintageMusclecar]

Aaron;

What heads are on your engine now?--they should be closed chamber oval ports (290 castings) if they're `70 LS5 heads.

Assuming a standard bore and flat top &quot;rebuilder&quot; type pistons (which usually wind up ~.020&quot; or so down in the hole) with a ~3 c.c. intake valve relief, a 106 c.c. chamber and a .018&quot; steel shim head gasket, compression would be roughly 8.8-1. I definitely would <span style="text-decoration: underline">not</span> run the LS6 cam with that combination, esp. with a stock converter, a 3.31 gear and A/C.

The factory LS5 cam isn't bad, but there is room for improvement. A mild hydraulic roller would be a nice addition, but given your constraints, I'd advise erring on the conservative side. If you're willing to take the chance on a hydraulic flat tappet, there are ample choices there as well.

In all honesty, I think you'd find more performance improvements in a good torque converter and some more rear end gearing than you would in a cam swap. A quality free-flowing exhaust system is also paramount.